…building civilizations with my space elves in space.

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So, I gather more’n a few laser fans are coming to visit these days, so just to save time, here’s the canonical reason that lasers are the ‘verse’s secondary weapons system, not its primary one:

(It turns out that this is really a recapitulation of points raised in Non-Standard Starship Scuffles, so if you’re already nodding along to that, you can more or less skip the rest. I’ll just hit a few high points.)

Lasers, for the most part, are useful weapons systems under many circumstances. (Obviously they have to be, given their use as point-defense; if you couldn’t get effective results from lasing a k-rod, they wouldn’t be used.) As mentioned elsewhere, you can get an effective result out of a laser weapon, due to collimation, up to around a light-second, which is the entirety of the inner engagement envelope, and as such every military starship mounts a passel of phased-array plasma lasers for point-defense, and larger classes cram in some broadside offensive lasers too.

You can actually collimate reasonably effective beams at rather longer distances than that, as the existence of starwisp tenders demonstrates – although they themselves are of little use for military purposes despite the incidents mentioned in that article, seeing as they shift angular vector and alter their focus with all the grace and speed of apatosauruses mating. One would, however, make a dandy generator for a laser web.

(Yes, they exist in the ‘verse, and have done ever since the Admiralty paid the Spaceflight Initiative to launch Sky-Shield, the homeworld’s first orbital defense grid, back in the day. Orbital defense grids remain their main military use, along with civilian beamed power.)

It’s just that the IN sees no particular point in paying in either cashy money or mass/volume budget for collimation to make them effective beyond the inner engagement envelope, because you aren’t going to hit any actively evading targets at that range anyway, golden BBs and spies having gotten you a copy of their drunkwalk algorithms aside, and kinetics/AKVs work better for the geometry games played in the outer envelope.

Here, though, is the spoiler in the deck where military lasers are concerned:

Thermal Superconductors.

(The laws of physics do permit them, I am assured, and local materials science is more than up to producing them.)

In up-to-date designs, starship armor is woven through with a dense mesh of the stuff, with wicking into big heat-sink tanks of thermal goo. This causes something of a problem for weaponized lasers, because it makes it ridiculously hard to create a hot spot that’ll vaporize – instead, you just add heat to the whole starship. Which is not useless by any means, if you can manage lots of repeated hits or keep a beam on target, because if you can pump enough heat into a starship, either it, the crew, or both, will go into thermal shutdown; but this is what lasers are for in ‘verse starship combat. If you want to blast things apart, you go for kinetics, because you can’t tank (sic) big lumps of baryons.

Of course, this defense has its limitations: a laser grid at short range can hit its target with enough power to overcome the armor and, indeed, to chop its target neatly into a pile of small cubes. But that’s for definitions of short range meaning “inside knife-fight range”, and any Flight Commander who let the range close that much without having his entire propulsion bus shot off first would be summarily cashiered for incompetence.

And that’s why lasers aren’t the primary or only weapons system around these parts.

Well, we can say that it is both entirely true and entirely useless (in actual space combat, although on the ground your mileage may differ).

It’s entirely true because, as Larry Niven said, “A reaction drive’s efficiency as a weapon is in direct proportion to its efficiency as a drive,” and obviously torch drives that let you tool around the system at consistent single-digit g accelerations are very efficient drives indeed. Unless you are using incredibly exotic, non-standard-molecular-matter materials, anything you park directly behind a torch drive will evaporate like a pat of butter under a blowtorch. No question.

It’s entirely useless because, as Atomic Rockets points out, “propulsion exhaust is poorly collimated, which means after a very short range it will have expanded and dissipated into harmlessness”. This is even perfectly deliberate as well as unintentional – it’s a basic safety feature for being able to use drives in the vicinity of anything else, ever. As such, unless you’re at point-blank range, you won’t be teaching this particular lesson – and if you let someone reach point-blank range in anything capable of being Kzinted, or make doing so part of your offensive plan, you fail space warfare tactics forever. Note that the inner engagement envelope begins at an entire light-second.

So, basically, if you want to weaponize your drive, stick to something that’s supposed to be collimated. Like launching lasers, or one of these.

(So there’s this trope which I missed when I originally put my list together (and which I will no doubt get to again in due course).

It’s called Standard Starship Scuffle, and it pretty much encapsulates every TV-scifi cliche imaginable. So, y’know, since I now have various fictive people critiquing it in my head with extra sarcasm, here’s some metafictional commentary on the way things actually work:)

…

Detection and Stealth

Before you can engage the enemy, you must first detect the enemy. Paradoxically, this is both extremely easy, and rather difficult.

To begin with, detection itself is easy. There is, to sum up many an armchair strategist’s lament, no stealth in space. Running the life support alone makes a starship stand out 300K hotter – for warm-blooded oxygen-breathers – than the background of space. Using power plant, thrusters, weapons systems, or anything else aboard only makes it more visible. Starships stand out plainly against the near-absolute cold of space, even across entire star systems, and this is inescapable.

Stealth, such as it is, would be better described as masquerade. One cannot avoid being detected; but one may be able to avoid being identified, or identified correctly. Performing such masquerades by altering one’s sensor signature is an important part of the function of a military starship’s defense drones.

It is difficult, on the other hand, because light, that sluggard, imposes an absolute limit on the currency of the data available. No sensor yet developed is capable of detecting objects in real time at a distance: at best, one can see what the situation was when light left that region.

Longscan

The answer to this is longscan.

Shortscan is what one’s own starship’s sensors, passive and active, are reporting.

Longscan, on the other hand, is the informational gestalt of that shortscan information along with all informational available from other sources (other starships in one’s formation or elsewhere in the system; tactical observation platforms; civilian navigation buoys or stargates, when available; and so forth), along with AI predictive extrapolations of what each starship or other object visible in longscan has done since the last update and/or will do, based on further extrapolations of what their longscan is telling them – and projections, likewise, of what they can know about your actions.

(Establishing this is in turn complicated by the nature of the tactical networks that provide that informational gestalt; modern navies provide their ships with tangle channelFTL communications between themselves and their own observation platforms, but since tangle-channel relays are point-to-point, this does not apply to most civilian sources except, in wealthier systems, as relays between STL EM communications buoys. Determining the “shape of the information wave” – who can know what, and when – is one of the most complex problems a warship’s tactical department faces.)

All of this information is displayed upon the tactical display, along with probability and reliability estimates, in graphical form. Learning how to read these tactical displays at a glance is, in itself, a significant part of naval officer training.

Observation Platforms

One of the greatest advantages one can have, therefore, is expanding one’s informational gestalt. Thus, virtually all military starships carry observation platforms with them for ad hoc deployment; and indeed, most navies routinely seed their own systems (and neutral systems in which they may operate) with dormant, concealed observation platforms awaiting activation when necessary by starships on the scene.

It is, of course, much harder to sneak concealed observation platforms into the sovereign systems of other polities, current enemy or not, and as such the information advantage in invasion scenarios is almost always with the defender.

Information Warfare

The nature of this data environment highlights the importance of information warfare in naval operations. One of the most valuable things it is possible to achieve, when still maneuvering for engagement, is to successfully infiltrate the tactical network of the opposing force. While direct stealth in space is impossible, the ability to distort one’s sensor signature, inject fake signatures, and otherwise falsify the information upon which one’s opponent is basing their tactical decisions is extremely valuable.

As a result, any major naval engagement is invariably accompanied by high-intensity information warfare, as each side attempts to corrupt the tactical networks and other data systems of the other.

An even greater coup, of course, is to penetrate the internal networks of an opposing starship and, having established a degree of computer control, simply order it to drop its kinetic barriers, shut down its point defense, vent its fuel, disable its life support, or otherwise change sides. Although remarkably difficult to achieve at the best of times, such a victory is almost always complete.

Offensive Systems

Mass Drivers

The main weapons system of most military starships, mass drivers propel solid, dense-metal slugs at extremely high velocities (a respectable fraction of c). These are usually pure kinetic energy weapons (KEWs); at the velocities attained by the projectiles, the damage done by KE alone renders most warheads superfluous.

(While provision is made on some larger vessel classes to add antimatter warheads to mass driver projectiles, it is usually thought that the increased potential for damage is more than offset by the additional potential risk posed by a magazine full of antimatter.)

Of these, the primary is usually a spinal mount weapon (since a longer accelerator barrel is capable of achieving higher terminal velocities, and therefore greater impact), aimed by pointing the entire ship, although most of these are capable of firing between 30 and 40 degrees off-bore by magnetic field adjustments. Larger ship classes include banks of “broadside” railguns, capable of firing both forward and to the side, for additional flexibility.

Lasers

Usually considered the secondary weapons system, the majority of military starships also mount banks of “broadside” lasers separate from the point-defense laser grid, intended to pump heat into targeted enemy vessels. Due to the nature of modern armor (see below) they rarely do significant direct damage, but contribute significantly to the task of wearing down one’s opponent.

An AKV is, in effect, a small, stripped-down, AI-piloted starship – capable of much higher acceleration and greater maneuverability than a standard design, albeit with much less endurance – designed to act in multiple roles – as a mobile reconnaissance platform; as a “fighter craft” used to swarm and destroy larger starships from inside their own point-defense zones; or, when it loses all other fighting ability, as a kinetic energy weapon in its own right.

Other

For the sake of completeness, it is also worth mentioning two other potential offensive systems. These are:

First, gravitic weapons: which are not a specific weapons system in themselves, but which constitute repurposing standard tractor-pressor functionality in order to grab, shake, crush, shear, etc. other vessels. These do possess a slight advantage inasmuch as they cannot be shielded against other than by precise counteruse of one’s own gravitics, and as such software for this is included in most tactical suites. However, since using such weapons requires closing to a range far below even “knife-fight” range and placing oneself not only within the inner engagement envelope but deep within the point defense envelope of one’s opponent, they are almost never of any practical use.

Second, one’s drive, the high-temperature emissions from any reaction drive in use being very readily weaponizable; anything in the danger zone when such a drive is activated tends to melt like wax under a plasma torch. Its practical limitation, however, for any drive smaller than a lighthugger’s, is again that one must close upon the enemy to an unacceptable degree before this use is possible – although leftover superheated and/or radioactive emissions may pose an environmental hazard in a “knife-fight range” battlespace.

Defensive Systems

The innermost of a starship’s defensive systems is its armor. The primary armor is a multilayer (“honeycomb”) system over the core hull, composed of multiple vacuum-separated layers of refractory cerametals, sapphiroids, and artificially dense metal nanocomposites, strapped together via flexible, shock-absorbing forms. Atop this, a thick sprayed-on layer of foamed-composite ablative armor (whose vaporized form is designed to scatter incoming energy weapon fire) provides additional protection.

To provide thermal protection, each of these layers is threaded through with a mesh of thermally superconducting material, preventing heat input from lasers or other energy weapons from creating localized “hot spots”. This mesh spreads out external heat inputs, and ultimately dumps them into tanks of “thermal goo”, an artificial substance of very high specific heat capacity. Under normal circumstances, this heat is disposed of via the ship’s radiative striping and external radiators, but if necessary, the thermal goo can be vented to space, taking its heat (and, unfortunately, its heat capacity) with it.

Outside the armor, starship defenses come in three more layers:

First and innermost, the kinetic barriers. These are not a single, all-encompassing bubble; rather, they are a grid of plates of gravitic force, instantiated as needed to intercept incoming material objects. (They cannot shield against massless radiation.) They don’t attempt to directly retard incoming projectiles; rather, their job is to “slap them aside”, imposing enough sideways vector on them to generate a miss.

Outside that, the defense drones: a military starship at general quarters surrounds itself with a “cloud” of small defense drones, serving multiple purposes: as electronic warfare platforms to obscure its signature; as participants in the kinetic-barrier generation and point-defense grid; as additional sensors; and ultimately, as sacrificial platforms capable of physically intercepting incoming projectiles or AKVs before they reach the ship itself.

Outermost is the point-defense zone guarded by the point-defense laser grid, extending substantially outward from the ship itself. Composed of phased-array plasma lasers which can be generated across large regions of the starship’s hull, the point-defense grid is used to vaporize incoming projectiles (or to use partial vaporization to decelerate incoming projectiles for the kinetic barriers and armor to deal with more effectively) and to force AKVs operating nearby – which have relatively little heat-dissipation capacity – into thermal shutdown.

The point-defense laser grid can also be used as an offensive weapon against any other starships unwise enough to stray into its range, but few captains are stupid enough to bring their starship into another ship’s point-defense zone.

The final defensive system that any starship has is drunkwalking: when at any alert state higher than peacetime cruising, every military starship engages in a pseudo-random “drunk walk” of vector changes around its station-keeping point or base course. This ensures that the starship is almost impossible to achieve a firing solution upon from a distance, since its movement since your most current observation of the target is unknown, and further increases the difficulty of achieving a solid firing solution in close.

(Of course, this depends greatly upon the quality of your drunkwalk algorithms and that they have been kept secure from the opposing force, which again underscores the importance of information warfare in the modern battlespace. A starship whose base course is identifiable and whose drunkwalk algorithms are known is a sitting duck even in the outer engagement envelope!)

A Note on Classes

The armament mix described above is accurate, in a well-balanced form, for cruiser and battlecruiser class military starships. These have been chosen as representative for the purpose of tactical illustration, as the classes designed specifically to operate independently.

Other, more specialized classes have different armament mixes (comparing, for instance, the mass driver-heavy armament of a battleship or a destroyer with the AKV-heavy armament of a carrier) intended to operate in interdependent squadrons. Operations involving these classes will not be covered in detail at this level, although certain specific details will be mentioned where relevant.

Engagement Envelopes

All battles in space take place at what are, by groundside standards, extremely long ranges, measured in ten-thousands, hundred-thousands, or millions of miles. Not only do these battles take place outside visual “eyeball” range, but even starships in the same formation are outside visual range of each other, being hundreds or thousands of miles apart. (Closer formations would pose both an unacceptably high risk of collision under battle conditions, when ships in the formation are drunkwalking independently, and would be likely to cause point-defense fratricide.)

The only exception to this rule are AKVs themselves (even when not acting as auxiliary KEWs), which often come within single-digit mile distances of their targets; i.e., operating effectively inside the innermost point-defense zone.

Outer Envelope: The Wolves at Hunt

The outer engagement envelope begins, depending on various environmental factors, at between one to one-half light-minutes range.

Battles taking place in the outer engagement envelope are essentially always inconclusive. While historical examples of lucky hits from these ranges do exist, the probabilities of such are sufficiently low that no-one would count on them; and at such ranges, it is virtually always possible for the weaker opponent to disengage at will.

(The exception being, of course, when someone has managed to sneak an observation platform in close to the opposing force without them noticing it, which gives them a great – albeit temporary – advantage in generating long-range firing solutions.)

Rather, the purpose of engagements in the outer envelope is to wear down an opponent closing upon one’s inner envelope, forcing them to generate heat and expend point-defense resources; and to herd opponents away from the danger zones generated by one’s fire.

While it is impossible, without both fortunate geometry and superior acceleration, for a single force to bring an opposing force to battle if it is actively trying to refuse such, it is sometimes possible through strategic outer-envelope engagement and misdirection to force them to pass through the inner engagement envelope of one of a set of multiple forces (including, for this purpose, fixed system defenses). This is the end to which tactics are directed in the outer engagement envelope.

At these ranges, the primary weapons are the spinally-mounted mass drivers of larger ship classes. Carriers may attempt to use “missiles” – actually strap-on, discardable thruster packs – to deliver AKVs close in to the opposing force, but many captains prefer to reserve their AKVs for inner-envelope battles where they can be better supported.

Inner Envelope: Let’s Dance

The inner, close-range engagement envelope – in which actual battles are fought – begins at roughly a light-second of separation. This reflects the difficulties of accurately targeting an opponent engaged in active evasion (drunkwalking, ECM, etc.) when the light-lag is greater than that; essentially, you have to close to within a light-second to get a firing solution whose hit probability is significant.

Reaching the inner engagement envelope implies either that one party is attacking or defending a specific fixed installation (such as a planetary orbit, drift-habitat, or stargate), or that both parties have chosen engagement. It is relatively rare for such battles to take place in open space otherwise, since in the absence of clear acceleration superiority, it is usually easy for the weaker party to disengage before entering their opponent’s inner engagement envelope. The only way to guarantee that an opponent will stand and fight is to attack a strategic nexus that they must retain control over.

Within the inner engagement envelope, all weapons come into play. Light lag becomes low enough that information warfare can come into play in full force, firing solutions are usually possible on all craft, and AKVs have the range and maneuverability to be committed.

Cautious admirals also hold their screening forces back at this point, preferring to weaken the enemy force before pressing further. More aggressive admirals press in immediately, moving their lighter squadrons into the center of the battlespace and deploying AKVs likewise.

Unlike the larger ships, cruisers maneuver aggressively for advantage, forming the characteristic “furball” as fleets intermingle; once this stage is reached, it becomes very difficult to retreat in good order. Cruisers attack each other with close-in, off-bore mass driver projectiles and heat-pumping lasers; the highly maneuverable destroyers and frigates engage in “wolf-pack” tactics throughout the battlespace, both targeting each other, and swarming damaged larger ships at relatively close range.

Knife-fight Range

Any battle in which the battlespace is smaller than a tenth of a light-second in diameter is referred to as taking place at “knife-fight” range. Such engagements usually occur around fixed points when the attack is pressed hard, are short and vicious, and typically result in extraordinarily high casualties – usually for both sides.

Defeat

Unlike starship armor, neither the point-defense laser grid nor the kinetic barriers are subject to direct attrition; if subjected to low-volume or low-power incoming fire, either or both could continue to destroy or repel it essentially forever.

In order to defeat these defensive systems, it is necessary to swamp them; to concentrate incoming fire to the point at which the defensive systems are unable to handle it all simultaneously. At this point, attrition may take effect as kinetic effectors and laser emitters are destroyed, but more importantly, it generates heat.

Heat is the primary limitation on combat endurance. Maneuvering burns, the use of high-energy equipment such as the point-defense grid, the kinetic barriers, and so forth, as well as the ship’s normal operation, all produce heat. In combat – when the ability to radiate heat is limited, usually to radiative striping and small (and exhaustable, if the starship is forced to maneuver) droplet radiators alone – military starships generate heat more rapidly than they can radiate it to space. As heat increases beyond the critical point, the efficiency of onboard equipment begins to fall (processor error rates rise, for example, and tactical officers must conserve their remaining heat capacity), some equipment goes into thermal shutdown, and the crew spaces become increasingly uninhabitable.

While some starships in any major space battle are destroyed physically, reduced to hulks, the majority of starships are defeated by either heat-induced equipment failure, or by being forced to surrender and deploy radiators lest their crew literally cook.